Combination telescopic and articulated aerial bucket device

ABSTRACT

A combination telescopic and articulated aerial bucket device has a boom assembly including a swingable member pivotally mounted on one telescopic section and pivotally connected through linkage structure to a second telescopic section. Relative hydraulic shifting of the two sections causes the linkage structure to effect swinging of the member to elevate an aerial bucket at the outer end thereof. Four species of the device embody alternative linkage structure and corresponding mounting arrangements for the swingable member.

United States Patent inventors George II. Eckels Prairie Village; Wade A. Eskridge, Overland Park, both of, Kans. Appl. No. 856,706 Filed Sept. 10, 1969 Patented Sept. 14, 1971 Assignee A. B. Chance Company Centralia, Mo.

COMBINATION TELESCOPIC AND ARTICULATED AERIAL BUCKET DEVICE 18 Claims, 14 Drawing Figs.

US. Cl 182/46,

182/2 Int. Cl 866i Il/04 Field of Search 182/2, 141,

II II m 1. l I l pg igmtd [56] References Cited UNITED STATES PATENTS 3,149,694 9/1964 Smithee... 182/2 3,286,855 11/1966 Bill 1. 182/2 3,477,588 11/1969 Reischl 212/55 Primary Examiner-Reinaldo P. Machado Attorney-Schmidt, Johnson, Hovey & Williams ABSTRACT: A combination telescopic and articulated aerial bucket device has a boom assembly including a swingable member pivotally mounted on one telescopic section and pivotally connected through linkage structure to a second telescopic section. Relative hydraulic shifting of the two sections causes the linkage structure to effect swinging of the member to elevate an aerial bucket at the outer end thereof. Four species of the device embody alternative linkage structure and corresponding mounting arrangements for the swingable member.

George H. Eckels Wade A. Eskridge ATTORNEYS.

PATENTEDSEPMIHYI 3504.533

SHEET k (If 4 j INVEN'IORS. 328 George H. Eclgels BY Wade A. Eskr'Idge ,QTTORNEYS.

COMBINATION TELESCOPIC AND ARTICULATED AERIAL BUCKET DEVICE The present invention relates to boom assemblies and, more particularly, to a combination telescopic and articulated serial device which utilizes the hydraulic extension of a telescopic boom section to efiect the extension of a swingable boom section.

Telescoping serial devices are better suited for certain jobs than articulated aerial devices. However, in in some instances, overhanging branches, wires and the like limit the use of such telescoping devices because of the straight line movement of their boom sections during extension thereof and the positioning limitations of their support vehicles relative to the overhanging obstructions. In instances such as these the inclusion of a swingable boom section among the telescoping sections to present a combination telescopic and articulated aerial device would often permit the aerial bucket at the outer end of the device to be extended around the obstruction. I

Additionally, it has been common practice among utility companies and the like to employ different types of machines for ground level digging work, low level derrick work, and higher elevational aerial bucket work. The additional expense involved by this practice could be avoided if these functions were combined into a single, multipurpose utility vehicle wherein the aerial boom structure operates as an extension of the derrick structure.

One problem with constructing an aerial device which combines telescopic and swingable boom sections or which may be used in combination with other apparatus such as diggers and telescopic derricks on utility vehicles has been to provide a convenient means for actuating the swingable section. Such actuating means must not interfere with the operation of other tools of the utility vehicle, nor with the extension of the telescopic boom sections of the device. While hydraulic cylinder assemblies may be appropriate when the swingable section is located at the lower end of the aerial device, such assemblies present considerable problems when the swingable section is at the outer end of the boom structure or intermediate the telescopic sections thereof. Likewise, such hydraulic assemblies are often inappropriate when the swingable section is adapted for combination with the telescopic derrick structure of a multipurpose utility vehicle.

Accordingly, it is an important object of the present invention to overcome the problems set forth above by providing a combination telescopic and articulated aerial device having a boom assembly wherein the extension of a swingable section pivotally mounted on one of the telescopic sections is effected by linkage structure interconnecting the swingable section and another telescopic during relative, straight line extension of the two telescopic sections.

Another important object of the invention is to provide a boom assembly as aforesaid which is prepared for aerial bucket work and adapted to be incorporated into a vehicular hoisting unit having components combining the functions of a hydraulic digger and a derrick so that separate vehicles for aerial bucket work and digger-derrick work may be eliminated. In this respect, it is a significant object of the invention to provide such an incorporation wherein the derrick component of the hoisting unit includes the telescopic boom sections which cooperate with linkage structure to actuate the extension of the swingable boom section.

A further important aim of this invention is the provision of an aerial device having an assembly as described, wherein the telescoping boom section may be operated independently of the swingable boom section.

An additional object of the invention is to provide an aerial device having an assembly as described, wherein the swingable boom section is pivotal through an are greater than 180 so that increased maneuverability of the assembly is obtained.

Yet another object of the instant invention is to provide a combination telescopic and articulated mobile aerial device of compact construction in which the swingable boom section may be folded down into overlyingrelationship to the telescopic boom sections so the vehicle may be driven under relatively low underpasses. i

A further aim of the present invention is to provide such an aerial bucket device in which the swingable boom section may be folded down into side-by-side relationship with the telescopic sections.

In the drawings:

FIG. 1 is an elevational view of a mobile, multipurpose hoisting unit incorporating one embodiment of a boom assembly made in accordance with the teachings of the present invention. The boom assembly is shown in its over-the-road position, partially extended position, and fully extended position while digger and derrick components of the hoisting unit are illustrated in their independent operable positions by dashed lines;

FIG. 2 is an enlarged, fragmentary elevational view of the boom assembly of FIG. 1 in its over-the-road position;

FIG. 3 is a fragmentary, top plan view thereof;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a fragmentary, cross-sectional view taken along line 5-5 of FIG. 4;

FIG. 6 is-a fragmentary, elevational view of a second embodiment of the present invention;

FIG. 7 is a fragmentary, top plan view thereof;

FIG. 8 is a fragmentary, elevational view of a third embodiment of the instant invention;

FIG. 9 is a fragmentary, top plan view thereof;

FIG. 10 is a fragmentary, elevational view thereof with the swingable boom section being shown in its overcenter position;

FIG. I l is an elevational view of a fourth embodiment of the present invention shown in use with a high elevation mobile aerial bucket device;

FIG. 12 is an elevational view thereof showing the aerial device collapsed in its over-the-road position;

FIG. 13 is an enlarged, fragmentary, top plan view thereof; and

FIG. 14 is a fragmentary, elevational view of the fourth embodiment shown partially extended.

v, FIGS. 1-5 show swingable boom structure combined w-w ith telescopic digger-derrick apparatus 22 of the type illustrated in US. Pat. No. 3,306,373 on the body ofa mobile vehicle 24, the combination of structure 20 and apparatus 22 presenting one embodiment of a combination telescopic and articulated aerial device 25 of the present invention. The digger-derrick apparatus 22 is mounted on the vehicle 24 by a rotatable turret 26, the apparatus 22 being pivotally mounted on the turret 26 for raising and lowering by a hydraulic cylinder assembly 28.

Apparatus 22 includes a tubular first boom section 30 pivotally mounted at one end thereof to the turret 26, a second boom section 32 telescoped into section 30 and supported on a roller 33 for extension from section 30 by a hydraulic cylinder assembly 34, and an auger assembly 36 shown held in its stowed position in FIG. 1. The auger assembly 36 may be shifted to various locations by the extension of section 32 and lowered to its operating position for digging holes for utility poles or the like as shown in FIG. 1. Assembly 36 is hinged to one end of an arm 38 normally extending across boom section 30 therebeneath, the arm 38 being pivotally attached at its opposite end to a collar 40 loosely embracing boom section 32.

A transfer link 42 rotatably pinned to the collar 40 has a lower cam edge normally in engagement with arm 38 and a hooked portion engageable with pin means 44 on boom section 32 spaced from the collar 40. As shown in FIG. 2, the arm 38, when disposed in a substantially horizontal position by the lifting of auger assembly 36 to its stowed position, raises the transfer link 42 from engagement with pin 44 to allow section 32 to be extended from section 30 withouteffecting the shifting of auger assembly 36. Lowering of auger assembly 36 to its operable position also lowers arm 38 and causes transfer link 42 to engage pin 44, thus interconnecting section 32 and assembly 36 for shifting the latter laterally over fences and the like. A winch and/or sheave assembly 46 is provided at the outer end of the section 32 includes a pair of sheave plates 48 rotatably supporting a sheave 50 therebetween.

The swingable boom structure shown in FIGS. 1-4 includes a boom member 52 pivotally mounted on section 32 by a mounting assembly 54 for swinging movement relative to the section 32 toward'and away from a collapsed location wherein member 52 substantially overlies section 30. A brace 56 on the top surface of section 30 supports member 52 when the latter is disposed in its collapsed location. Structure 20 further includes a pair of link arms 58 and 60 disposed on opposite sides of the section 30 and operably interconnecting the latter and member 52, the arms 58 and 60 being pivotally coupled at one end respectively to opposite sides of section 52 adjacent the inner end thereof by a shaft 62 and at their opposite ends respectively by a shaft 64 through the section 30.

Member .52 comprises an elongated metal sleeve 66 which rigidly receives at its outer end thereof an elongated, tubular, fiber glass reinforced synthetic resin boom unit 68, and, optionally a separate tubular, synthetic resin, glass fiber reinforced boom element 70 telescoped within unit 68 for extension therefrom by a cylinder assembly 72. A pintle 74 at the outer end of element 70 or element 68 if element 70 is omitted, pivotally secures an aerial bucket 76 thereto, the bucket 76 being free to gravitationally maintain an upright disposition during raising and lowering of the device 25. Hydraulic lines 78 from a suitable pump means run through the tubular arm 60 and extend through sleeve 66 to ultimately couple with cylinder assembly 72.

The components of mounting assembly 54 (FIG. 5) include a generally U-shaped mounting plate 80 rigidly secured on the top surface of section 32 adjacent winch assembly 46, the upturned sides of plate 80 presenting a pair of spaced, openmouthed yokes 82 adapted for receiving a pivot shaft 84 extending therebetweemLug means 86, projecting outwardly from the bottom surface of sleeve 66 intermediate the ends of member 52 receives shaft 84 in suitable bearing means to mount member 52 for its swinging movement. A cylinder assembly 88 rigid to plate 80 actuates a pair of spaced links 90 pivotally connected at one end respectively to a pair of spaced, hooked locking clamps 92 hinged to each of the yokes 82 for releasable engagement with the shaft 84. It may be seen that uponactuation of cylinder 88 to release locking clamps 92 from shaft 84, the section 32 may be extended from section 30 without effecting any swinging movement of member 52. Sleeve 66 is provided with elongated opening 94 therethrough disposed in alignment with the assembly 46 to provide clearance for the latter when section 52 swings about shaft 84.

In operation, the aerial bucket device may be collapsed in a compact arrangement as shown in FIG. 1 for transportation thereof to and from a job site with the bucket 76 being tilted to a prone position. Upon reaching the job site and initially positioning the vehicle 24 in a location adjacent the elevated work area, a workman may enter the bucket 76 for subsequent elevation to the area. Actuation of the cylinder assembly 28 will raise section to the positions illustrated in FIG. 1, whereupon actuation of cylinder assembly 34 causes section 32 to be extended. At the same time, while section 32 is extending, if clamps 92 are locked about shaft 84, the member 52 travels outwardly with the section 32. However, the link arms 58 and 60 connected to the stationary section 30 remain behind and pull the inner end of member 52 downwardly whereby member 52 is caused to fulcrum about an essentially horizontal axis through shaft 84 in a clockwise direction viewing FIG. 1, to raise bucket 76 to an elevated position, such position being directly related to the amount of extension of section 32 from section 30.

During the elevation of bucket 76 the assembly 46 is free to pass through opening 94 in sleeve 66 whereby the device 25 may be extended to its fully elevated position. Further longitudinal extension of the optional element 70 from unit 68 provides additional height for bucket 76 if such extra height is needed.

Upon retraction of the section 32, a counterclockwise swinging movement of the member 52 occurs viewing FIG. 1 as the link arms 58 and 60 push out on the inner end of member 52 to fold the latter into its location overlying section 30. It will be appreciated that the bucket 76 is maintained in an upright position during elevation and lowering thereof, while the fiberglass reinforced synthetic resin construction of unit 68 and element 70 provides electrical insulation for the workman in bucket 76 and those in and around the vehicle 24. Further, the employment of link arms 58 and 60 as a means for translating the longitudinal extension of section 32 into swinging motion of member 52 eliminates the need for additional bulky cylinder assemblies or other actuating devices for effecting the extension of member 52.

Should it be desired to use section 32 as independent derrick apparatus instead of as a telescoping section of the aerial device 25, it is only necessary to actuate the cylinder assembly 88 of mounting assembly 54 to release the locking clamps 92 from engagement with shaft 84. At such time, inasmuch as section 32 is no longer joined to member 52, the latter will remain supported by link arms 58 and 60 and the bracket 56 on section 30 while section 32 is extended for use. It will be seen that section 32 may be raised to any of the positions shown in FIG. 1 while functioning as a derrick apparatus without interference from member 52.

FIGS. 6 and 7 relate to a second embodiment of the invention wherein the aerial device 125 includes swingable boom structure combined with telescopic digger-derrick apparatus 122 corresponding so that shown inFlGS. l-5. In this embodiment, the apparatus 122 includes a tubular first boom section 130 telescopically receiving a second extensible boom section 132 and an auger assembly (not shown). A winch and/or sheave assembly 146 is provided at the outer end of section 132, and a mounting assembly 154 on section 132 pivotally mounts a boom member of structure 120 on section 132 for swinging movement thereabout to and from a stored location offset from and to one side of section 130. Member 152 comprises a metal sleeve 166 having a fiberglass reinforced synthetic resin ele ment 168 rigidly received therein.

Structure 120 further includes an elongated link arm 158 hingedly coupled at one end to the inner end of member 152 by a shaft 162 and at the opposite end to one side of section 130 by a shaft 164. The mounting assembly 154 has components similar to those of the first embodiment including a rigid mounting plate 180 on section 132, a pair of spacedapart yokes 182, and a pair of hooked locking clamps 192 actuated by a cylinder assembly 188 and links 190. A cantilevered pivot shaft 184 carried by suitable bearing means in member 152 extends outwardly therefrom between the yokes 182 to be releasably held by clamps 192.

The operation of the aerial device is substantially similar to that of device 25 of the first embodiment. It will be seen, however, that the major distinction between the two embodiments is that member 152 of device 125 is offset from section to one side thereof, while member 52 of device 25 is disposed in overlying relationship to the section 30. Accordingly, in its stored location, the member 152 is disposed slightly lower than member 52 of device 25 whereby to present a relatively more compact device 125 for storage or transportation thereof to and from a work site.

With the locking clamps 192 engaging the pivot shaft 184, upon longitudinal extension of section 132, member 152 is caused to fulcrum about shaft 184 as link arm 158 pulls the inner end of member 152. Retraction of section 132 causes swinging movement of member 152 in the opposite direction as link arm 158 pushes against the inner end thereof to bring member 152 toward its stored location.

Once again, the releasable nature of the mounting assembly 154 permits the extension of section 132 independently if member 152, whereby section 132 may be employed as a derrick apparatus.

FIGS. 8-10 relate to a third embodiment of the invention wherein the serial device 225 shows swingable boom structure 220 in combination with telescopic digger-derrick apparatus 222 corresponding to that of the first two embodiments. Apparatus 222 includes a tubular first boom section 230 telescopically receiving a second boom section 232 for longitudinal extension therefrom, the section 232 being provided with a winch and/or sheave assembly 246 at the outer end thereof. A boom member 252 of structure 220 comprising a sleeve 266 and a synthetic resin glass fiber reinforced element 268 rigidly received therein is mounted for swinging movement relative to section 230 by mounting means 254 including a cantilevered pivot shaft 284 which extends between a pair of plates 255 on section 230 and outwardly therefrom. It will be seen that in the first two embodiments of the invention respective members 52 and 152 were pivotally mounted to the extensible boom sections 32 and 132, while in the present embodiment, member 252 is mounted on the relatively stationary boom section 230 for swinging movement thereabout to and from a stored position offset from and to one side thereof.

Structure 220 also includes linking means interconnecting the sections 230, 232 and member 252 and having a plurality of legs 285, 285a, 285b, and 285C pivotally connected for rotation about a common shaft 287. The leg 285 is pivotally connected to member 252 by a shaft 289 remote from shaft 287 and the legs 285a and 285s are spaced on opposite sides of section 230 to pivotally embrace the latter by means of a shaft 291 therethrough also remote from shaft 287. A hub 293 is provided on shaft 287 between the ends of legs 285a and 285C to maintain separation of the latter. A releasable coupling assembly 295 rigidly secured to section 232 comprises components which are substantially identical in their construction and operation to those of the mounting assemblies 54 and 154 of the first two embodiments, although, in the present embodiment, the components of coupling assembly 295 perform a different function as will hereinafter be seen. Assembly 295 includes a generally U-shpaped mounting plate 280, the upstanding sides of which present a pair of spaced yokes 282, and a pair of hooked locking clamps 292 actuated by a cylinder assembly 288 and links 290. The leg 285b is secures at one end to hub 293, and has at its opposite end a relatively short, rigid cross shaft 297 which is releasably and pivotally held by yokes 282 and clamps 292 whereby to couple the member 252 to section 232.

With the coupling assembly 291 in engagement with the shaft 297, extension of the section 232 causes leg 285b to pull the cooperating legs 285, 285a and 2850 whereby to swing member 252 about shaft 284. As shown best in FIG. 10, the present embodiment permits member 252 to assume an overcenter position upon full extension thereof wherein an arc greater than 180 has been traversed. Retraction of the section 232 causes swinging movement of the member 252 in the opposite direction as leg 285b pushes against hub 293 member 252 toward its stored location above and to one side of section 230.

It will be seen that hydraulic release of the locking clamps 292 permits the extension of section 232 independently of any swinging movement of member 252 whereby section 232 may be utilized as a derrick apparatus.

FIGS. 11-14 relate to a fourth embodiment of the present invention wherein swingable boom structure 320 is combined with telescoping boom structure 322 to present a combination telescopic and articulated high elevational aerial bucket device 324. The telescoping structure 322 is hingedly mounted on a turret 326 which, in turn, is rotatably mounted on a mobile vehicle 328.

The telescopic structure 322 includes four tubular, relatively telescoped boom sections 330, 322, 334 and 336. A main hydraulic cylinder assembly 338 interconnects turret 326 and section 330 for raising and lowering the device 324. A second cylinder assembly 340 interconnecting sections 330 and 332 exteriorly thereof is provided for extending the latter from section 330, there being a third cylinder assembly 342 interconnecting sections 332 and 334 interiorly thereof for extending the latter from section 332, and a fourth cylinder assembly 334 interconnecting sections 334 and 336 interiorly thereof for extending the latter from section 334.

The swingable boom structure 320 includes a boom member 345 comprising a metal sleeve 346 rigidly receiving a synthetic resin glass fiber reinforced boom element 347 which has an aerial bucket 348 attached to its outer end thereof. The member 345 is mounted for swinging movement relative to section 336 by mounting means 350 including a pivot shaft 352 rigid to a collar 353 at the outer end of section 336. Lug means 354 extending outwardly from the bottom of sleeves 346 has suitable bearing means for receiving the shaft 352. A pair of spaced link arms 356 are pivotally connected at one end respectively to a rigid collar 358 on section 334 by a shaft 360, and at their opposite ends to the inner end of member 345 by a shaft 362 through sleeve 346. It is to be noted that sleeve 346 is open in the area adjacent lug means 354 whereby to permit clearance for the outer end of section 336 upon full extension of device 324 as shown in FIG. 11.

As shown in FIG. 12, the aerial device 324 is collapsed for storage or travel to and from a work site, and in this position, the retracted boom sections 330-336 are supported by an upright brace 364 on the body of the mobile vehicle 328. Also at this time, the swingable boom member 345 is collapsed into its stored location overlying the section 330.

Upon arrival at thework site and subsequent positioning of the vehicle 328, the aerial device 324 may be extended by successively actuating the cylinder assemblies 338-384. Upon extension of section 336 by cylinder assembly 344, the mounting assembly 350 is carried therewith to subsequently shift member 345 away from section 334. At this time the link arms 356, being retained by collar 358, pull the inner end of member 346 to cause the latter to swing about shaft 352 whereby to elevate bucket 348. Retraction of the section 336 causes a swinging movement of member 346 about a shaft 352 in the opposite direction as the link arms 356 cooperate to push the inner end of section 346 and lower bucket 348.

It may be seen that the combination of telescopic and swingable boom structures, as illustrated in the present embodiment, permit an aerial device capable of reaching great heights to be constructed without fear of violating highway overall length requirements when the device is collapsed for transportation thereof.

It will be appreciated that the invention as illustrated in the four embodiments described herein combines the favorable characteristics of a telescoping aerial device with those of an articulating aerial device. In addition, the provision of linking structure in each embodiment for actuating the swingable boom section upon extension of an adjacent telescoping boom section eliminates many of the problems which would be associated with providing hydraulic systems for actuating the swingable sections.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. A boom assembly comprising:

a pair of elongated boom elements, one of said boom elements being shiftable endwise relative to the other boom element;

a boom member;

means pivotally mounting said member on said one boom element for swinging movement relative thereto; and

structure operably connecting the other of said elements to said member for effecting said swinging movement of the latter upon endwise shifting of said one boom element relative to the other boom element.

2. In a boom assembly as set forth in claim 1, wherein said one element is disposed in telescoping relationship to said other element for extension therefrom.

3. In a boom assembly as set forth in claim 2, wherein said member is mounted on said one element in disposition for said swinging movement toward and away from a location generally overlying said other element.

4. In a boom assembly as set forth in claim 3, wherein said structure includes a pair of link arms on opposite, respective sides of said other element, each of said link arms being pivotally coupled to the adjacent ends of said other element and the member respectively.

5. A boom assembly as set forth in claim 2, wherein said member is mounted on said one element in disposition for swinging movement toward and away from a location generally offset from and to the side of said other element.

6. A boom assembly as set forth in claim 5, wherein said structure includes an elongated link arm between the other element and said member and pivotally joined to each of the latter.

7. A boom assembly as set forth in claim 2, wherein said mounting means includes releasably interengageable components operable upon release thereof to permit said one element to be extended from said other element without effecting said swinging movement of the member.

8. A boom assembly as set forth in claim 1, wherein said other element is disposed in telescoping relationship to said one element for extension therefrom.

9. A boom assembly as set forth in claim 8, wherein said structure includes a plurality of hingedly interconnected legs pivotal about a common axis, one of said legs being pivotally mounted remote from said axis on said member, another of said legs being pivotally mounted remote from said axis on said one element, there being means for pivotally coupling a third of said legs to said other element in spaced relationship from said axis.

10. A boom assembly as set forth in claim 9, wherein said coupling means includes releasably interengaging parts operable upon release thereof to permit said other element to be extended from said one element without effecting said swinging movement of the member.

11. A boom assembly as forth in claim 11, wherein at least one of said units is constructed of electrically nonconductive material.

12. A boom assembly as set forth in claim 1, wherein is provided a third boom element, said other element being in shiftable telescoped relationship to said third element for extension therefrom.

13. An aerial bucket device adapted to be mounted on a mobile vehicle, said device comprising:

a rotatable base assembly;

a pair of elongated, telescoped boom elements pivotally mounted on said base assembly for swinging movement relative thereto, one of said boom elements being shiftable endwise relative to the other boom element;

power means for effecting shifting of said one element relative to the other element;

an elongated boom member;

means pivotally mounting said member on said one of the elements for swinging movement relative thereto;

bucket means pivotally mounted movement on said member adjacent one end thereof; and

link structure adjacent the opposite of said member pivotally interconnecting the latter and said other element for effecting said swinging movement of the member upon said powered relative shifting of the elements.

14. An aerial bucket device as set forth in claim 13, wherein said one element is received within said other element for extension therefrom.

15. An aerial bucket device as set forth in claim 14, wherein said mounting means includes releasable, hydraulically actuated latch means, said elements being operable independently of said member upon release of said latch means.

16. An aerial bucket device as set forth in claim 14, wherein is provided a third boom element, said other element being telescoped within said third element for extension therefrom.

17. An aerial bucket device as set forth in claim 13, wherein said other element is received within said one element for extension therefrom.

18. An aerial bucket device as set forth in claim 17, wherein said link structure includes a plurality of legs pivotally connected for rotation about a common axis, one of said legs being pivotally mounted on said member remote from said axis, another of said legs being pivotally mounted on said one element remote from said axis, and a third of said legs being pivotally mounted on said other element remote from said axis. 

1. A boom assembly comprising: a pair of elongated boom elements, one of said boom elements being shiftable endwise relative to the other boom element; a boom member; means pivotally mounting said member on said one boom element for swinging movement relative thereto; and structure operably connecting the other of said elements to said member for effecting said swinging movement of the latter upon endwise shifting of said one boom element relative to the other boom element.
 2. In a boom assembly as set forth in claim 1, wherein said one element is disposed in telescoping relationship to said other element for extension therefrom.
 3. In a boom assembly as set forth in claim 2, wherein said member is mounted on said one element in disposition for said swinging movement toward and away from a location generally overlying said other element.
 4. In a boom assembly as set forth in claim 3, wherein said structure includes a pair of link arms on opposite, respective sides of said other element, each of said link arms being pivotally coupled to the adjacent ends of said other element and the member respectively.
 5. A boom assembly as set forth in claim 2, wherein said member is mounted on said one element in disposition for swinging movement toward and away from a location generally offset from and to the side of said other element.
 6. A boom assembly as set forth in claim 5, wherein said structure includes an elongated link arm between the other element and said member and pivotally joined to each of the latter.
 7. A boom assembly as set forth in claim 2, wherein said mounting means includes releasably interengageable components operable upon release thereof to permit said one element to be extended from said other element without effecting said swinging movement of the member.
 8. A boom assembly as set forth in claim 1, wherein said other element is disposed in telescoping relationship to said one element for extension therefrom.
 9. A boom assembly as set forth in claim 8, wherein said structure includes a plurality of hingedly interconnected legs pivotal about a common axis, one of said legs being pivotally mounted remote from said axis on said member, another of said legs being pivotally mounted remote from said axis on said one element, there being means for pivotally coupling a third of said legs to said other element in spaced relationship from said axis.
 10. A boom assembly as set forth in claim 9, wherein said coupling means includes releasably interengaging parts operable upon release thereof to permit said other element to be extended from said one element without effecting said swinging movement of the member.
 11. A boom assembly as forth in claim 11, wherein at least one of said units is constructed of electrically nonconductive material.
 12. A boom assembly as set forth in claim 1, wherein is provided a third boom element, said other element being in shiftable telescoped relationship to said third elemeNt for extension therefrom.
 13. An aerial bucket device adapted to be mounted on a mobile vehicle, said device comprising: a rotatable base assembly; a pair of elongated, telescoped boom elements pivotally mounted on said base assembly for swinging movement relative thereto, one of said boom elements being shiftable endwise relative to the other boom element; power means for effecting shifting of said one element relative to the other element; an elongated boom member; means pivotally mounting said member on said one of the elements for swinging movement relative thereto; bucket means pivotally mounted movement on said member adjacent one end thereof; and link structure adjacent the opposite of said member pivotally interconnecting the latter and said other element for effecting said swinging movement of the member upon said powered relative shifting of the elements.
 14. An aerial bucket device as set forth in claim 13, wherein said one element is received within said other element for extension therefrom.
 15. An aerial bucket device as set forth in claim 14, wherein said mounting means includes releasable, hydraulically actuated latch means, said elements being operable independently of said member upon release of said latch means.
 16. An aerial bucket device as set forth in claim 14, wherein is provided a third boom element, said other element being telescoped within said third element for extension therefrom.
 17. An aerial bucket device as set forth in claim 13, wherein said other element is received within said one element for extension therefrom.
 18. An aerial bucket device as set forth in claim 17, wherein said link structure includes a plurality of legs pivotally connected for rotation about a common axis, one of said legs being pivotally mounted on said member remote from said axis, another of said legs being pivotally mounted on said one element remote from said axis, and a third of said legs being pivotally mounted on said other element remote from said axis. 